Facts are, not two guns with succesive serial numbers are dimensionally the same in the bore which is the part most critical to accuracy. There's a few 10/10000ths spread in bore, groove and chamber dimensions that make a difference. And sometimes the rifling twist ain't perfectly uniform across them.
The biggest difference between what folks get with a given rifle and ammo selection is how well they shoot it. A given rifle will produce different accuracy levels with the same ammo across dozens of people shooting it. They all don't hold it and fire it the same way for each shot. And they all use different standards for measuring accuracy.
All of which is why, in a test ran decades ago with a .308 Win. match rifle that shoots 1/4 moa all day long from a free recoil rest, produced test groups from almost 1/2 MOA to a whole full 2 MOA size 5-shot groups at 100 yards as shot by a couple dozen people shooting it from a bench with its fore end and stock toe resting on bags and held against their shoulder when fired.
Go figure this out.
Lost sheep, Rifle barrels of identical dimensions and weight are the same in stiffness and the resonance of harmonic vibration. If they were not, then all the mechanical engineering formulas used by professionals calculating fixed beam stiffness would be out of a job. The same dimension numbers used for a given metal's modulus of elasticity gives the same resonant frequency.
US Navy Distinguished Marksman Badge 153
Former US Navy & Palma Rifle Team Member
NRA High Power Master & Long Range High Master
NRA Smallbore Prone Master
Last edited by Bart B.; December 28, 2012 at 01:31 PM.